Magdalena Owczarek

[NH2(C2H4)2O]MX5: a new family of morpholinium nonlinear optical materials among halogenoantimonate(III) and halogenobismuthate(III) compounds. Structural characterization, dielectric and piezoelectric properties

This paper presents the structural features of ionic complexes formed by morpholine and metal ions which belong to group VA, namely Sb(III) and Bi(III). A series of target inorganic-organic hybrid compounds of the general formula [NH(2)(C(2)H(4))(2)O](2)MX(5) (where M = Sb, Bi; X = Cl, Br) has been synthesized by incorporating the organic component (morpholine) into the highly polarizable one-dimensional halogenoantimonate(III)/halogenobismuthate(III) chain network. Among the studied compounds, four were found to crystallize in the room temperature phase in the piezoelectric, orthorhombic space group P2(1)2(1)2(1), Z = 4, the feature being confirmed by the powder second harmonic generation of light and piezoelectric measurements. Dielectric dispersion studies between 200 Hz and 2 MHz disclosed a relaxation process below room temperature well described by the Cole-Cole equation. Based on crystal structures available in Cambridge Structural Database (version 5.32, November 2010) we attempt to show a relationship between the acentric symmetry of compounds and the type of anionic network within the R(2)MX(5)-subgroup (where R denotes organic cation) of halogenoantimonates(III) and halogenobismuthates(III).

Flexible ferroelectric organic crystals.

Flexible organic materials possessing useful electrical properties, such as ferroelectricity, are of crucial importance in the engineering of electronic devices. Up until now, however, only ferroelectric polymers have intrinsically met this flexibility requirement, leaving small-molecule organic ferroelectrics with room for improvement. Since both flexibility and ferroelectricity are rare properties on their own, combining them in one crystalline organic material is challenging. Herein, we report that trisubstituted haloimidazoles not only display ferroelectricity and piezoelectricity—the properties that originate from their non-centrosymmetric crystal lattice—but also lend their crystalline mechanical properties to fine-tuning in a controllable manner by disrupting the weak halogen bonds between the molecules. This element of control makes it possible to deliver another unique and highly desirable property, namely crystal flexibility. Moreover, the electrical properties are maintained in the flexible crystals.

Redox-Active Macrocycles for Organic Rechargeable Batteries

Organic rechargeable batteries, composed of redox-active molecules, are emerging as candidates for the next generation of energy storage materials because of their large specific capacities, cost effectiveness, and the abundance of organic precursors, when compared with conventional lithium-ion batteries. Although redox-active molecules often display multiple redox states, precise control of a molecules redox potential, leading to a single output voltage in a battery, remains a fundamental challenge in this popular field of research. By combining macrocyclic chemistry with density functional theory calculations (DFT), we have identified a structural motif that more effectively delocalizes electrons during lithiation events in battery operations-namely, through-space electron delocalization in triangular macrocyclic molecules that exhibit a single well-defined voltage profile-compared to the discrete multiple voltage plateaus observed for a homologous macrocyclic dimer and an acyclic derivative of pyromellitic diimide (PMDI). The triangular macrocycle, incorporating three PMDI units in close proximity to one another, exhibits a single output voltage at 2.33 V, compared with two peaks at (i) 2.2 and 1.95-1.60 V for reduction and (ii) 1.60-1.95 and 2.37 V for oxidation of the acyclic PMDI derivative. By investigating the two cyclic derivatives with different conformational dispositions of their PMDI units and the acyclic PMDI derivative, we identified noticeable changes in interactions between the PMDI units in the two cyclic derivatives under reducing conditions, as determined by differential pulse voltammetry, solution-state spectroelectrochemistry, and variable-temperature UV-Vis spectra. The numbers and relative geometries of the PMDI units are found to alter the voltage profile of the active materials significantly during galvanostatic measurements, resulting in a desirable single plateau for the triangular macrocycle. The present investigation reveals that understanding and controlling the relative conformational dispositions of redox-active units in macrocycles are key to achieving high energy density and long cycle-life electrodes for organic rechargeable batteries.

Weak hydrogen and dihydrogen bonds instead of strong N–H⋯O bonds of a tricyclic [1,2,4,5]-tetrazine derivative. Single-crystal X-ray diffraction, theoretical calculations and Hirshfeld surface analysis

Octahydro-1H,6H-bis[1,4]oxazino[4,3-b:4′,3′-e][1,2,4,5]tetrazine, 1, and its monohydrated analog, 2, were obtained by an oxidation process of N-aminomorpholine with iodine. Both compounds crystallize in monoclinic space groups P21/c and C2/c for 1 and 2, respectively. Despite the presence of a strong hydrogen bond donor – the NH group – the crystal packing of 1 is determined by weak C–H⋯O and C–H⋯N hydrogen bonds. In order to explore more precisely this intriguing fact, the theory of Atoms In Molecules (AIM) was used to examine intermolecular interactions in a crystal. An analysis of the topological properties of electron density with the determination of bond critical point revealed a set of contacts which were carefully scrutinized to determine whether they fulfill the criteria of hydrogen and dihydrogen bond existence in the AIM method. Their stability was checked by DFT calculations. In the case of 2, the crystal packing is realized by strong O1w–H1w⋯N and N–H⋯O1w hydrogen bonds with water. The possibility of accepting more than one hydrogen atom by each lone electron pair of water is discussed based on the AIM method and Natural Bond Orbital (NBO) analysis. Hirshfeld surfaces were employed to confirm the existence of intermolecular interactions in 1 and 2.

The low-temperature phase of morpholinium tetra­fluoro­borate

The crystal structure of the low-temperature form of the title compound, C4H10NO+·BF4 −, was determined at 80 K. Two reversible phase transitions, at 158/158 and 124/126 K (heating/cooling), were detected by differential scanning calorimetry for this compound, and the sequence of phase transitions was subsequently confirmed by single-crystal X-ray diffraction experiments. The asymmetric unit at 80 K consists of three BF4 − tetrahedral anions and three morpholinium cations (Z′ = 3). Hydrogen-bonded morpholinium cations form chains along the [100] direction. The BF4 − anions are connected to these chains by N—H⋯F hydrogen bonds. In the crystal structure, two different layers perpendicular to the [001] direction can be distinguished, which differ in the geometry of the hydrogen bonds between cationic and anionic species.

Morpholinium chloroindate(III) complex: a rare acentric structural arrangement leading to piezoelectric properties

Among materials with six-membered aliphatic rings coordinated to a metal center, the [C4H10NO]+[InCl5(C4H10NO)]− morpholinium complex is a rare example of a system characterized by a polar crystal structure. The noncentrosymmetry results from the unidirectional alignment of the z components of the dipole moments of both anionic and cationic units. The anomalies observed on the electric permittivity curves are characteristic of acentric materials and confirm that the crystals possess piezoelectric properties. A discussion regarding the potential ferroelectric properties of the compound is provided.